Self sufficiency in energy is a stated national goal. Most of the proposed means to achieve this goal are either environmentally unacceptable or are not feasible, especially those not depending on fossil fuel sources. Of the available alternatives, solar energy is the most abundant, inexhaustable single resource available. However, capturing and utilizing solar energy is not simple. Methods are being sought to convert solar energy to a concentrated, storable form of energy.
One method of converting solar energy to a usable form being prominently considered is the deployment of large arrays of photovoltaic solar cells, especially in the sunbelt areas such as the southwestern and western regions of the United States. The most promising candidate for the solar cell is a doped silicon material and silicon is one of the most plentiful elements in the earth's crust. However, the economic feasibility depends on processing cost and presently the most efficient cells are produced from pure single crystal silicon.
There is a need for lower cost solar cell grade silicon. Chromium is one of the inherent impurities of concern in metallurgical grade silicon. Presently chromium is removed from silicon utilized for solar cell manufacture at substantial cost since the chromium impurity is electrically active, forming deep traps which substantially impair performance of solar cells.